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Sonoma sbc turbo build

hey guys, names jesse.. been on s10forum and whatnot for a long long time.. decided to come on here since you guys are all gods of the small blocks and what needs to be done.. Anyways a overview of what i got, its a 2001 sonoma on full airsuspention, custom interior and bed, all that jazz. Last year i decided to pull the 2.2 out and build my first 350 and stick it in. Block is a 78 c10 2-bolt, installed a thumper cam and some vortech heads, performer intake and a 750 edelbrock carb. Put down 330hp and 375tq on the dyno last winter. Well this year its time for a big change. I bought a 78 4-bolt block for 50$ from a guy at work and gonna stick that in, but will also be adding a turbo to this one. Was thinking about doing a twin but would run into major clearance issues on the drivers side so i will be doing a single. I will be purchasing the turbo kit/headers/wastegate hopefully next friday and i will be going from there and peiceing everything else together. Also got a few other plans i will be doing over winter to.. but as for now the list goes and i kno much more will be needed:
- LSD rear end
- holly 750 carb converted blowthrew
- Single turbo
- Line-lock on breaks
- Electronic cut-out

and heres some of the truck:
http://i817.photobucket.com/albums/zz100/pearl01chevy/Sonoma/Interior/SL374906.jpg[/IMG]

And heres how she sits currently, taking a/c box out and putting heater only in:

the turbo was installed and had all the exhaust piping done and then i sold it. So sadly no i never got to see it run. Always wondered how it woulda been though.. And having said that it makes me confident to complete this build!

Hopefully this post gets some much needed attention in the threads!! hah
Starting out pretty much got the radiator/support done, still need to throw some filler on there and do a final paint but im happy with the turnout! its nice and flush so ill have more space in the engine compartment.
and FINALLY my turbo kit came!! Been a long week and half wait but im sooo happy its here! Turbo is alot bigger then i expected
The wastegate
And the headers/crossover pipe, i can only use the passenger header for clearance issues.. and btw i didnt even have this kit in my garage for a hour before i started cutting it up to fit haah

And heres another clearance issue which is not alllowing the turbo to sit flush on the header plate
And the wastegate tube needs to be moved up i say 2inchs and ill be good with that
And heres the money shots!
And lastly i sent my 4bolt block yesturday to the machine shop!

originally i wanted to do a twin turbo setup. But with the headers thats sold for the twin kit the turbo would be setting where the mastercylinder is for the breaks. And i was seaching around and found a 1/4 and 1/2" spacer so i can space out the turbo if i need to, but im about to run down and move it and see if theres a difference. Also i kno ill need to wrap that turbo

but anyways.. i called the machine shop today and talked to them. They said the 4bolt block would need a bore so i said screw it and doing 30over. So now ill have a 355.. And the other question i got for now is this is the cam i got in the truck currently, would this be alright to run with my turbo? or should i look elseware

That looks like a supercharger/nitrous cam. I would look for something more turbo friendly.

Have you thought about using a smaller sized CS130 alternator that will put out as much amps as that 12SI alternator? I used the same header and had to make a low mount alternator setup to clear the 12SI and a Garrett T04E compressor with a smaller/lower .84 A/R turbine. The CS130 would have been a better choice.

i honestly dont understand cams to much, can ya go more into details if its not to big of a deal thanks!

Reversion only has a negative effect w/superchargers, not turbo chargers. The cycling rate w/turbo's is high during boost, and even during idle speeds, any charge that escapes through overlap is being used to spin the turbine. It isn't necessarily wasted. Not so with superchargers of course, which is why boost pressure suffers with too much overlap because the boost escapes quench and heads straight to the exhaust. No turbine. Run the cam you have, it should work well for you...

Vast majority of turbo cams out there do not look like that I still think there will be some reversion regardless if theres a turbo or not on the exhaust. Thats a big duration overlap event on a smaller motor. All cammed cars with decent overlap have reversion at idle and sometimes low engine speeds.

The better the design is for the turbo system, from headers to turbine sizing, generally see less and less back pressure. The closer you are to 1 to 1 ratio of intake boost/exhaust backpressure, or even to the point of LESS exhaust backpressure vs intake boost pressure, the more closely the Cam can match a n/a type motor spec. I wouldnt use that cam, but it may "work" it just wont work as well as it could.

I doubt that header design will show less back pressure vs boost pressure so the overlap on the cam should be cut down.

The beauty w/reversion in his turbo application is that he will get the added benefit of even more higher RPM perfomance to be used w/that GT45 turbo. Common flat spot's w/reversion in naturally aspirated applications will not apply here, and the charge is literally instantaneous, even at idle speeds. The turbine cannot differentiate between a burned mixture, or an unburned mixture, it only knows to move when being pressurized to do so, so in the end all pressure is being forced through the exhaust valve, regardless. I for one even noticed a decrease in EGT when switching from a 116-LSA down to a 110-LSA, more than likely due to the slight amount of unburned and colder air entering into the turbine exhaust housing...

EGT would drop due to unburned mixture. Did that not affect turbine performance? Heat is a key element in getting spool but so is exhaust pressure pulse energy which is related to the heat.

I've only seen one other setup that used a tight 108 lsa cam and it runs hard. Blown385 I think his name was on TTF.com. Has the turbo sonoma or s10? Low 9 second almost high 8 second ride then? It was a tighter duration split cam, but tight LSA.

EGT would drop due to unburned mixture. Did that not affect turbine performance? Heat is a key element in getting spool but so is exhaust pressure pulse energy which is related to the heat...

The drop was not significant enough, nor substantial enough to negatively effect the efficiency of the turbo, but just enough to see that difference. The turbo is going to get hot, regardless. Not to mention, I would much rather see a slight decrease in EGT's to help maximize a more denser and oxygenated intake charge, as opposed to keeping the turbo at it's hottest point, then resting on the hopes that the intercooler does it's job of lowering air temperature, even on a brutal summer day. It is essentially a healthy compromise between the two. Could always run anti-lag/two step as well w/that cam and turbo...

well for ***** and giggles decided to threw my old hood on and check to see how much i'd have to cut the hood up for the turbo, i sput the one side of the turbo so it wasnt pointing up anymore and it helped out but.. boy was i suprised.. i got a crapload of room between the hood and the turbo so im extremely happy with that. I even added a temporary 1/4" spacer between the turbo and the header to get it up off the valve cover and alternator.

mines a major pain to pull.. cant pull motor / trans seperate, have to pull em together ( 4l80e is so huge in the trans tunnel..) which means i have to take off radiator, core support etc.. and come straight out the front with it...

Motor is stripped down and ready to sell
Just curious why would the cam look like this on spots?
Also im a bit weary of this timing gear after seeing this..
Also instead of drilling and tapping a hole in the oil pan for a return like, couldnt i just drill and tap into this plate??
and the wheel wells are out, bout to start the long process of getting that frame cleaned up

Finally finally got my block back, some info on it: bored .30 over, magnafluxed, cleaned, hoaned, new cam bearings installed and new freeze plugs installed.. man oh man not a nice bill but in the end it was so worth it. she sooo pretty!!
And this is gonna get outta control quick since im so picky.. frames getting por-15

I'd rather see forged pistons and h-beam rods with good bolts for a turbo car but do what you can with your budget. Pistons can live if the tune is right. Spend money on the rods/rod bolts to be most safe.

Not sure what heads you were going to use or if you are keeping this a 355 or going 383 but flat tops with a 355 and 64cc head is low 10's to 1 compression. With a 383 thats 11 to 1. Too high for boost. I like 9-9.5 to 1 with aluminum heads. Would need a small dish piston.

for now i plan on keeping the vortech heads, going to put roller rockers on them also and possibly change the springs.. and yes i do plan on keeping it a 355. and thanks for that tip.. back to searching!

Avoid the Kieth Blacks. The ring lands are a lot higher up on them than a traditional piston. This makes it a weaker land, as well as making it more likely the rings will but. If you do use them I would strongly advise looking at their web site as I do believe they have a modified gap chart. I suspect that's a reason why people have issues with them.

They may live if you dont push them hard enough and dont run the chamber so hot. But if you are doing this right the first time, it makes sense to atleast have forged pistons. They are much more forgiving than hyper's

hahaha same here.. but how hard are you ACTUALLY pushing yours?? mines only a weekend driver and maybe the strip here and there.. just something to play around with, nothing serious.. would this pass for the pistons posted above?? also any suggestions on rods??

No not saying that they are the absolute best but I would use em way before the kbs. My buddy went mid 11s wit a buick v6 on the trw hypers though. 27lbs boost and he did about 75 of spray too. Keeps eating cams but the pistons are fine. Ton of street miles and track time. Open the gaps up too, that is probably a big part of it as well.